Currently, positron emission tomography (PET) imaging relies upon 18F as the positron emitter, typically in the form of fluorodeoxyglucose (FDG), which is metabolized by active body tissue. With a short half-life of only 1.8 hours, radiopharmaceuticals containing 18F must be synthesized immediately before administration to patients near the cyclotron source of the element. Such a short half-life makes it difficult to use with antibodies and does not permit these radiopharmaceuticals to be used in radiotherapy.
Because of their significantly longer half-life than 18F, arsenic radioisotopes permit a much wider range of radiopharmaceuticals, including labeling biological vectors. As such, radiotherapeutic agents can then be developed for targeting a variety of diseases using arsenic radiolabeled biomolecules, adding to the arsenal of potential cancer therapeutics.
What is needed then are more reliable methods for preparing arsenic radioisotopes and compounds containing those radioisotopes.